File Format in the Mapping File

The mapping file consists of a series of separate tables. Each table
begins with its name. Names always have an alphabetic character in the first
column. The table name is followed by a required blank line, and then by the
entries in the table. Entries consist of zero or more indented lines. Each
entry must be preceded by at least one space. Each entry line consists of
two columns separated by one or more spaces or tabs. Any spaces within an
entry must be quoted using the $ character. A blank line must appear after
each mapping table name and between each mapping table; no blank lines can
appear between entries in a single table. Comments are introduced by an exclamation
mark (!) in the first column.

An application using the mapping table TABLE-2-NAME would
map the string pattern2-2 into whatever is specified by template2-2. Each pattern or template can contain up to 252 characters.
There is no limit to the number of entries that can appear in a mapping (although
excessive numbers of entries may consume huge amounts of CPU and can consume
excessive amounts of memory). Long lines may be continued by ending them with
a backslash (\). The white space between the two columns and before the first
column may not be omitted.

Duplicate mapping table names are not allowed in the mapping file.

Including Other Files in the Mapping File

Other files may be included in the mapping file. This is done with a
line of the form:

<file-spec

This effectively substitutes the contents of the file file-spec into
the mapping file at the point where the include appears. The file specification
should specify a full file path (directory, and so forth). All files included
in this fashion must be world readable. Comments are also allowed in such
included mapping files. Includes can be nested up to three levels deep. Include
files are loaded at the same time the mapping file is loaded—they are
not loaded on demand, so there is no performance or memory savings involved
in using include files.